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Now the Moon reveals its water

Green glass spherules, about 0.2 mm across, were collected from the Apollo 15 landing site at Hadley Rille on the Moon

(Image: NASA)

WE THOUGHT it was dry as a bone, but now it seems the moon’s parched surface has water hidden beneath it.

Alberto Saal of Brown University in Providence, Rhode Island, and colleagues re-examined lunar volcanic rocks collected in the 1970s during the Apollo 15 and 17 missions. They found up to 50 parts per million of water trapped in tiny spheres of volcanic glass.

That’s not much compared with the 500 to 1000 ppm of water in Earth’s mantle. Yet when the lava …